I can't recommend this game highly enough. It's rough around the edges and not everyone will like it (as you can see by the mixed reviews), but from a narrative standpoint, it's one of the most beautiful, atmospheric, and immersive experiences I've had in a video game. It just feels so different from everything else out there. Last time I felt this way was with Mirror's Edge. (It's also a very impressive tech demo.)

One of the best hardcore platformers out there. Even better now that it's no longer Flash-based!

Somewhat similar to Braid. Absolutely worth it.